//初始化状态
const initState ={
  countNum:1,
}
export default function countReducer(preState=initState,action){
  const {type,data} = action
  console.log("触发了reducers",action);
  switch (type) {
    case "R_countNum":
      return {...preState,countNum:data}
    default:
      return preState
  }
}
